Clothes, towels, sheets and so on, thought of as one pile that has to do with washing. The same word covers three moments in the pile's life: the dirty clothes waiting to be washed, the clothes going round inside the machine right now, and the clean wet clothes you have just taken out. You tell which one is meant from the rest of the sentence — "the washing is piling up" is dirty, "the washing is still going" is in the machine, "hang out the washing" is clean and wet. It is uncountable: one sock is not "a washing", and there is no plural "washings" in this everyday use. The word is British, Australian and New Zealand English above all; in the United States people usually say the laundry for the same pile. Note that British speakers use both — laundry is a slightly more neutral or written word, washing is the homey one. It is a completely ordinary word, not formal at all, and it lives in a small family of set phrases: do the washing (wash the clothes), hang out / hang up the washing, bring in the washing, a load of washing, the washing machine, washing powder, washing line, washing-up (which, careful, is dishes, not clothes). One more thing: washing is also just the -ing form of the verb wash, so "washing the car" and "the washing is dry" are two different grammatical animals wearing the same coat.